http://git.xfce.org/xfce/xfce-utils/patch/?id=96af982828d767763640c84f38b80bf0d3eb52b1

--- scripts/xinitrc.in.in
+++ scripts/xinitrc.in.in
@@ -131,7 +131,11 @@
 	x|xno*)
 		;;
 	*)
-		$xfcesm
+		if type ck-launch-session >/dev/null 2>&1; then
+			ck-launch-session $xfcesm
+		else
+			$xfcesm
+		fi
 
 		if test $kill_sshagent -eq 1; then
 			eval `$sshagent -k`